Letter from A. E. Demaray to Carl T. Hayden concerning the dates and participants of a congressional party visit that begins in San Francisco, Calif., and includes the Roosevelt-Sequoia National Park, Calif.; Needles, Calif.; Grand Canyon National Park, Ariz.; Flagstaff, Ariz.; Keams Canyon, Hopi Nation; Fort Defiance, Navajo Nation; Shiprock, Navajo Nation; and the Pueblo of Zuni.

The objective of this study was to evaluate the effect of typical chemical winter maintenance practices on Arizona Department of Transportation pavements. A review of previous studies on the effect of deicing/anti‐icing chemicals did not yield definitive recommendations, especially for DIAICs typically used by ADOT. Researchers conducted a laboratory study evaluating the effects of magnesium chloride, potassium chloride, sodium chloride, and distilled water on eight different open‐graded rubber‐modified asphalt concrete mixes using the boiling test. All experimental factors were found to be statistically significant, and the researchers provide recommendations on which DIAICs should be used for different binder and aggregate types.

This study investigated whether highways acted as barriers to gene flow for pronghorn in northern Arizona. DNA samples from 132 pronghorn were analyzed using eight polymorphic microsatellite loci. Samples represented animals living on opposite sides of US Route 89 (US 89) and State Route 64 (SR 64). Two different modeling approaches indicated that both US 89 and SR 64, and to a lesser extent US Route 180 (US 180), acted as barriers to gene flow. The genetic structuring caused by highways, especially across US 89, is consistent with behavioral data that demonstrated pronghorn rarely cross this highway. This study found no evidence of inbreeding or reduced genetic variation in any of the populations examined, but those effects may take longer to appear. Based on these results, the researchers recommend future genetic monitoring of these populations or assessment of genetic variation across highways with larger traffic volumes or longer histories to determine whether the barrier effects documented here lead to loss of genetic diversity.